Please do not take that as an insult, because it is most likely was not.

A lot of people from the oriental cultures would not ask for things even if they want something (because of their being a bit more reserved, being embarrassed, etc) and struggle on without asking for help.
I assume you are not from the orient - in which case, she is most likely to have given it to you to save you the potential embarrassment of asking for it in case you wanted it but did not want to ask because many people who are not from the orient do find it a bit hard to eat with chopsticks (or do not wish to eat with them). You could say it is wrong of them to assume that you would find it difficult to ask for things or that there was even a chance that you wanted a fork, but you cannot expect cabin crew members to be completely familiar with how every person thinks.

It's best try not to take things as an insult when it is likely that they did not intentionally try to insult you. It lessens the likelihood of being offended and leads to a more pleasant life

Anyway, which carrier was this? I see they served natto beans... good grief! While I do not mind it in a relatively open area, it is not something I wish to see on board (due to smell).